Hello dear!

You can't directly go for a research field after your b.sc you have options for pursuing research only after M.Sc

So for that complete your M.Sc (2years) in mathematics and then enter into research field through some exams conducted by research institutes

One more option is if your currently in degree 2nd or 3rd year start preparing for IIT-JAM ( indian institute of technology-join admission test for m.sc ) so here you will basically prepare for IIT JAM in mathematics paper ....so you will have an option to do 5year integrated program ( m.sc + ph.d )IISc and few other institutes will take admission based on your iit jam rank for this integrated course .

So without m.sc You further cant get into research field

Feel free to ask further more queries regarding this

All the best!!